Measurements of the Hubble constant and, more generally, measurements of the expansion rate and distances over the interval $0<z<1$ appear to be inconsistent with the predictions of the standard cosmological model ($\mathrm{\Lambda }\mathrm{CDM}$) given observations of cosmic microwave background temperature and polarization anisotropies. Here we consider a variety of types of departures from $\mathrm{\Lambda }\mathrm{CDM}$ that could, in principle, restore concordance among these datasets, and we explain why we find almost all of them unlikely to be successful. We single out the set of solutions that increases the expansion rate in the decade of scale factor expansion just prior to recombination as the least unlikely. These solutions are themselves tightly constrained by their impact on photon diffusion and on the gravitational driving of acoustic oscillations of the modes that begin oscillating during this epoch—modes that project on to angular scales that are very well measured. We point out that a general feature of such solutions is a residual to fits to $\mathrm{\Lambda }\mathrm{CDM}$, like the one observed in Planck power spectra. This residual drives the modestly significant inferences of angular-scale dependence to the matter density and anomalously high lensing power, puzzling aspects of a dataset that is otherwise extremely well fit by $\mathrm{\Lambda }\mathrm{CDM}$.

Individual supermassive black hole binaries in noncircular orbits are possible nanohertz gravitational wave sources for the rapidly maturing Pulsar Timing Array experiments. We develop an accurate and efficient approach to compute Pulsar Timing Array signals due to gravitational waves from inspiraling supermassive black hole binaries in relativistic eccentric orbits. Our approach employs a Keplerian-type parametric solution to model third post-Newtonian accurate precessing eccentric orbits while a novel semianalytic prescription is provided to model the effects of quadrupolar order gravitational wave emission. These inputs lead to a semianalytic prescription to model such signals, induced by nonspinning black hole binaries inspiraling along arbitrary eccentricity orbits. Additionally, we provide a fully analytic prescription to model Pulsar Timing Array signals from black hole binaries inspiraling along moderately eccentric orbits, influenced by Boetzel et al. [Phys. Rev. D 96, 044011 (2017)]. These approaches are being incorporated into Enterprise and TEMPO2 for searching the presence of such binaries in Pulsar Timing Array datasets.

We search for possible correlations between neutron star observables and thermodynamic quantities that characterize high density nuclear matter. We generate a set of model-independent equations of state describing stellar matter from a Taylor expansion around saturation density. Each equation of state which is a functional of the nuclear matter parameters is thermodynamically consistent, causal and compatible with astrophysical observations. We find that the neutron star tidal deformability and radius are strongly correlated with the pressure, the energy density and the sound velocity at different densities. Similar correlations are also exhibited by a large set of mean-field models based on nonrelativistic and relativistic nuclear energy density functionals. These model independent correlations can be employed to constrain the equation of state at different densities above saturation from measurements of NS properties with multimessenger observations. In particular, precise constraints on the radius of PSR $\mathrm{J}0030+0451$ thanks to NICER observations would allow to better infer the properties of matter around two times the nuclear saturation density.

We present the results of a systematic study of the constraints on neutrino neutral-current nonstandard interactions (NSIs) that can be obtained from the analysis of the COHERENT spectral and temporal data. First, we consider the general case in which all ten relevant neutral-current NSI parameters are considered as free. We show that they are very weakly constrained by the COHERENT data because of possible cancellations between the up and down quark contributions. However, the up-down average parameters are relatively well constrained, and the strongest constraints are obtained for an appropriate linear combination of up and down NSI parameters. We also consider the case in which there are only NSIs with either up or down quarks, and we show that the LMA-Dark fit of solar neutrino data is excluded at $5.6\sigma$ and $7.2\sigma$, respectively, for NSIs with up and down quarks. We finally present the tight constraints that can be obtained on each NSI parameter if it is the dominant one, assuming that the effects of the others are negligible.

We study the phenomenology of the scotogenic model in the case of a Majorana dark matter (DM) candidate. This scenario gives important consequences since the parameter space of the model is almost unconstrained compared to the inert Higgs doublet model (or the scotogenic model with scalar DM) and hence offers new opportunities for discovery at future high energy colliders, e.g., the HL-LHC. As an example, we focus on the production of the Standard Model (SM) Higgs boson in association with a pair of dark scalars. Owing to its clean signature, the $\gamma \gamma$ decay channel of the SM Higgs boson is investigated in great detail at both the HL-LHC (at $\sqrt{s}=14\mathrm{TeV}$) and the future FCC-hh (at $\sqrt{s}=100\mathrm{TeV}$). After revisiting the LHC constraints from run II on the parameter space of the model and selecting benchmark points satisfying all the theoretical and experimental constraints, we found that scalars with mass up to 140 GeV (160 GeV) can be probed at the LHC (FCC-hh) with a $3{\mathrm{ab}}^{-1}$ of integrated luminosity assuming a total uncertainty of 5%.

The complex scalar dark matter (DM) candidate in the gauged two-Higgs-doublet model, stabilized by a peculiar hidden parity ($h$ parity), is studied in detail. We explore the parameter space for the DM candidate by taking into account the most recent DM constraints from various experiments, in particular, the PLANCK relic density measurement and the current DM direct detection limit from XENON1T. We separate our analysis in three possible compositions for the mixing of the complex scalar. We first constrain our parameter space with the vacuum stability and perturbative unitarity conditions for the scalar potential, LHC Higgs measurements, plus Drell-Yan and electroweak precision test constraints on the gauge sector. We find that DM dominated by composition of the inert doublet scalar is completely excluded by further combining the previous constraints with both the latest results from PLANCK and XENON1T. We also demonstrate that the remaining parameter space with two other DM compositions can be further tested by indirect detection like the future Cherenkov Telescope Array gamma-ray telescope.

Within the minimal left-right (LR) symmetric model we revisit the predictions for the kaon $CP$ violating observables $ϵ$ and ${ϵ}^{\prime }$ in correlation with the neutron electric dipole moment. We perform a complete study of the cross constraints on the model parameters, phases and the $M_{W_R}$ scale, considering the two cases of extended parity or charge conjugation as LR discrete symmetries, together with the possible presence of a Peccei-Quinn symmetry. We discuss in particular two scenarios: whether the Standard Model saturates the experimental value of ${ϵ}^{\prime }/ϵ$ or whether new physics is needed, still an open issue after the recent lattice results on the QCD penguin matrix elements. Within the first scenario, we find no constraints on the LR scale in the charge-conjugation case while in the parity case we show that $M_{W_R}$ can be as low as 13 TeV. On the other side, the request that new physics contributes dominantly to ${ϵ}^{\prime }$ implies strong correlations among the model parameters, with an upper bound of $M_{W_R}<8–100\mathrm{TeV}$ depending on $\tan \beta$ in the case of charge conjugation and a range of $M_{W_R}\simeq 7–45\mathrm{TeV}$ in the parity setup. Both scenarios may be probed directly at future colliders and only indirectly at the LHC.

Effective field theory (EFT) approaches are widely used at the Large Hadron Collider (LHC), such that it is important to study their validity and ease of matching to specific new physics models. In this paper, we consider an extension of the Standard Model (SM) in which a top quark couples to a new heavy scalar. We find the dimension six operators generated by this theory at low energy and match the EFT to the full theory up to the next-to-leading order (NLO) precision in the simplified model coupling. We then examine the range of validity of the EFT description in top pair production, finding excellent validity even if the scalar mass is only slightly above LHC energies, provided NLO corrections are included. In the absence of the latter, the LO EFT overestimates kinematic distributions, such that overoptimistic constraints on beyond the Standard Model (BSM) contributions are obtained. We next examine the constraints on the EFT and full models that are expected to be obtained from both top pair and four top production at the LHC, finding for low scalar masses that both processes show similar exclusion power. However, for larger masses, estimated LHC uncertainties push constraints into the nonperturbative regime, where the full model is difficult to analyze, and thus is not perturbatively matchable to the EFT. This highlights the necessity to improve uncertainties of SM hypotheses in top final states.

We present results for the moments of nucleon isovector vector and axial generalized parton distribution functions computed within lattice QCD. Three ensembles of maximally twisted mass clover-improved fermions simulated with a physical value of the pion mass are analyzed. Two of these ensembles are generated using two degenerate light quarks. A third ensemble is used having, in addition to the light quarks, strange and charm quarks in the sea. A careful analysis of the convergence to the ground state is carried out that is shown to be essential for extracting the correct nucleon matrix elements. This allows a controlled determination of the unpolarized, helicity, and tensor second Mellin moments. The vector and axial-vector generalized form factors are also computed as a function of the momentum transfer square up to about $1{\mathrm{GeV}}^2$. The three ensembles allow us to check for unquenching effects and to assess lattice finite volume effects.

We present a general formalism to write the decay amplitude for multibody reactions with explicit separation of the rotational degrees of freedom, which are well controlled by the spin of the decay particle, and dynamic functions on the subchannel invariant masses, which require modeling. Using the three-particle kinematics we demonstrate the proposed factorization, named the Dalitz-plot decomposition. The Wigner rotations, which are subtle factors needed by the isobar modeling in the helicity framework, are simplified with the proposed decomposition. Consequently, we are able to provide them in an explicit form suitable for the general case of arbitrary spins. The only unknown model-dependent factors are the isobar line shapes that describe the subchannel dynamics. The advantages of the new decomposition are shown through three examples relevant for the recent discovery of the exotic charmonium candidate $Z_c(4430)$, the pentaquarks $P_c$, and the intriguing ${\mathrm{\Lambda }}_c^{+}\to p{K}^{-}{\pi }^{+}$ decay.

We provide a generic framework to obtain stable dark matter along with naturally small Dirac neutrino masses generated at the loop level. This is achieved through the spontaneous breaking of the global $U(1{)}_{B-L}$ symmetry already present in the standard model. The $U(1{)}_{B-L}$ symmetry is broken down to a residual even ${\mathcal{Z}}_n$ ($n\ge 4$) subgroup. The residual ${\mathcal{Z}}_n$ symmetry simultaneously guarantees dark matter stability and protects the Dirac nature of neutrinos. The $U(1{)}_{B-L}$ symmetry in our setup is anomaly free and can also be gauged in a straightforward way. Finally, we present an explicit example using our framework to show the idea in action.

We study the fermionic condensate (FC) and the vacuum expectation value (VEV) of the energy-momentum tensor for a massive spinor field in the de Sitter (dS) spacetime including an ideal cosmic string. In addition, spatial dimension along the string is compactified to a circle of length $L$. The fermionic field is assumed to obey quasiperiodic condition along the $z$-axis. There are also magnetic fluxes running along the cosmic string and enclosed by the compact dimension. Both, the FC and the VEV of the energy-momentum tensor, are decomposed into two parts: one induced by the cosmic string in dS spacetime considering the absence of the compactification, and another one induced by the compactification. In particular, we show that the FC vanishes for a massless fermionic field.

In this work, the production of hidden-bottom pentaquark $P_b$ states via $\gamma p$ and ${\pi }^{-}p$ scatterings is studied within an effective Lagrangian approach and the vector-meson-dominance mechanism. For the $P_b$ production in the process $\gamma p\to \mathrm{\Upsilon }p$, the dipole Pomeron model is employed to calculate the background contribution, and the experimental data can be well described. For the process ${\pi }^{-}p\to \mathrm{\Upsilon }n$, the Reggeized $t$-channel with $\pi$ exchange is considered as the main background for the $P_b$ production. The cross section from the $t$-channel $\pi$ exchange is very small due to weak coupling of $P_b$ state to the $\pi \pi$ channel predicted theoretically. Near the threshold, two-peak structure from the states $P_b(11080)$ and $P_b(11125)$ can be observed if energy bin width is chosen as 0.01 GeV, and the same result is obtained in the ${\pi }^{-}p$ scattering. Moreover, by taking the branching ratio of $\mathrm{Br}[P_b\to \pi N]\simeq 0.05\%$, the numerical result shows that the average value of the cross section from the $P_b(11080)$ state produced in the $\gamma p$ or ${\pi }^{-}p$ scattering reaches at least 0.1 nb with a bin of 0.1 GeV. Even if we reduce the branching ratio of the $P_b$ state into $\pi N$ channel by one order, the theoretical average of the cross section from $P_b(11080)$ production in ${\pi }^{-}p$ scattering can reach the order of 0.01 nb with a bin of 0.1 GeV, which means that the signal can still be clearly distinguished from the background. The experimental measurements and studies on the hidden-bottom pentaquark $P_b$ state production in the $\gamma p$ or ${\pi }^{-}p$ scattering near-threshold energy region around $W\simeq 11\mathrm{GeV}$ are strongly suggested, which are accessible at COMPASS and JPARC. Particularly, the result of the photoproduction suggests that it is very promising to observe the hidden-bottom pentaquark at the proposed EicC facility in China.

The nonperturbative path integral quantization of the electroweak model is confronted with an apparent instability when integrating over the Maxwell potential $A_{\mu }$ due to the fast growth of the box graphs $AAAA$ and $AAAZ$ for large amplitude variations of $A_{\mu }$. $Z_{\mu }$ is from the vector part of the weak neutral current. These graphs are unavoidable because they are conditionally convergent and have to be isolated in the model’s exact Euclidean one-loop effective action arising from its fermion determinants. A previous QED calculation of the large amplitude variation of its fermion determinant for a class of random potentials showed that the $AAAA$ box graph cancels in this limit. Using this result it is shown that within the electroweak model large amplitude variations of $A_{\mu }$ for fixed $Z_{\mu }$ in a superposition of these fields cancel the $AAAA$ and $AAAZ$ graphs, thereby removing an apparent obstacle to the model’s nonperturbative quantization. A negative paramagnetic term in the remainder opposes the effective action’s growth for such variations. Its calculation requires knowledge of the degeneracy of the bound states of a charged fermion in the four-dimensional magnetic fields generated by the functional measure of $A_{\mu }$.

Black hole “spectroscopy”, i.e., the identification of quasinormal mode frequencies via gravitational wave observations, is a powerful technique for testing the general relativistic nature of black holes. In theories of gravity beyond general relativity, perturbed black holes are typically described by a set of coupled wave equations for the tensorial field and the extra scalar/vector degrees of freedom, thus leading to a theory-specific quasinormal mode spectrum. In this paper we use the eikonal/geometric optics approximation to obtain analytic formulas for the frequency and damping rate of the fundamental quasinormal mode of a generalized, theory-agnostic system of equations describing coupled scalar-tensor perturbations of spherically symmetric black holes. Representing an extension of our recent work, the present model includes a massive scalar field, couplings through the field derivatives and first-order frame-dragging rotational corrections. Moving away from spherical symmetry, we consider the simple model of the scalar wave equation in a general stationary-axisymmetric spacetime and use the eikonal approximation to compute the quasinormal modes associated with equatorial and nonequatorial photon rings.

Analytic expressions for the statistics of peaks of random fields with weak non-Gaussianity are provided. Specifically, the abundance and spatial correlation of peaks are represented by formulas which can be evaluated only by virtually one-dimensional integrals. We assume the non-Gaussianity is weak enough such that it is represented by linear terms of the bispectrum. The formulas are formally given in $N$-dimensional space, and explicitly given in the case of $N=1$, 2, 3. Some examples of peak statistics in cosmological fields are calculated for the cosmic density field and weak lensing field, assuming the weak non-Gaussianity is induced by gravity. The formulas of this paper would find a fit in many applications to statistical analyses of cosmological fields.

Superradiant clouds may develop around a rotating black hole, if there is a bosonic field with Compton wavelength comparable to the size of the black hole. In this paper, we investigate the effects of the cloud on the orbits of nearby compact objects. In particular, we consider the dynamical friction and the backreaction due to level mixing. Under these interactions, the probability of a black hole dynamically capturing other compact objects, such as stellar mass black holes and neutron stars, is generally enhanced with the presence of the cloud. For extreme mass ratio inspirals and binary stellar mass binary black holes, the cloud-induced orbital modulation may be detected by observing the gravitational waveform using space borne gravitational wave detectors, such as LISA. Interestingly within certain range of boson Compton wavelength, the enhanced capture rate of stellar mass black holes could accelerate hierarchical mergers, with a higher-generation merger product being more massive than the mass threshold predicted by supernova pair instability. These observational signatures provide promising ways of searching light bosons with gravitational waves.

Two-dimensional scalar field theories with spontaneous symmetry breaking subject to the action of Jackiw-Teitelboim gravity are studied. Solutions for the ${\varphi }^4$ and sine-Gordon self-gravitating kinks are presented, both for general gravitational coupling and in the perturbative regime. The analysis is extended to deal with a hierarchy of kinks related to transparent Pöschl-Teller potentials.

A comprehensive analysis on the photon self-energy, the fermion self-energy, and the fermion vertex function is presented at one loop in the context of quantum electrodynamics (QED) with one extra dimension. In five-dimensional theories, characterized by an infinite number of Kaluza-Klein fields, one-loop amplitudes involve discrete as well as continuous sums, ${\sum }_{n=1}^{\infty }\int d^{4}k$, that could diverge. Using dimensional regularization, we express such sums as products of gamma and Epstein functions, both defined on the complex plane, with divergences arising from poles of these functions in the limit as $D\to 4$. Using the analytical properties of the Epstein function, we show that the ultraviolet divergences generated by the Kaluza-Klein sums can be consistently renormalized, which means that the corresponding renormalized quantities reduce to the usual ones of QED at the limit of a very large compactification scale $R^{-1}$. The main features of QED at the one-loop level were studied. We use the mass-dependent $\mu$-scheme to calculate, in QED with an arbitrary number $n$ of extra dimensions, a beta function fulfilling all desirable physical requirements. We argue that in these types of theories, with a large mass spectrum covering a wide energy range, beta functions should not be calculated by using mass-independent renormalization schemes. We show that the beta function is finite for any energy $\mu$. In particular, it reduces to the usual QED result $e^3/12{\pi }^2$ for $m\ll \mu \ll R^{-1}$ and vanishes for $m\gg \mu$, with $m$ the usual fermion mass. Throughout the work, the decoupling nature of all our results obtained from the analytical properties of the Epstein function is stressed.